Self-insulated expulsion fuse and support



July 15, 1930. J. E. SUMPTER SELF INSULATED EXPULSION FUSE AND SUPPORT Filed Aug. 2. 1926 2 Shuts-Sheet 1 910121: E. sumpter 1 July 15, 1930. J. E. SUMPTER 1,770,536

SELF INSULATED EXPULSION FUSE AND SUPPORT Filed Aug. 2, 1926 2 ShoethSheet 2 gnmntoz Patented July 15, 1930 UNITED STATES PATENT OFFICE JOHN E. SUMMER, 01' MINNEAPOLIS, MINNESOTA, ASSIGNOB TO DELTA-STAR ELEC- TRIO COMPANY, 01 CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS SEIiF-INSULATED EXPULSION FUSE AND SUPPORT Application filed August 2,

My invention relates to self-insulated expulsion fuse and support wherein it is de signed to provide a porcelain tube which is made 'of a high grade of porcelain best known as the wet process to provide a porcelain insulator, together with the means for supporting the porcelain tube and fuse.

A feature of my invention resides in means for supporting the porcelain tube in a manner so as to ordinarily take the place of the two insulators used in similar equipment wherein my expulsion fuse is employed.

It is also a feature of my invention to pro-. vide an air gap within the fuse fixture or porcelain casing between the body of the casing and the tubular insulating housing containing the fuse wire. This air gap permits the fuse fixture to be kept perfectly dry.

within the same, preventing any moisture from remaining up in the casing and also. forms a cooling medium for the fuse tube so that the heat from the burning of the fuse is not directly transmitted to the porcelain insulating casing.

It is also a feature of my invention to pro vide an expulsion fuse fixture which is adapted to act as a support for other electric equipment ordinarily associated with such style of expulsion fuse and to support the entire expulsion fuse and connecting parts with a single supporting means. This supporting means is adjustable to the expulsion fuse insulator.

The invention further involves an insulator wherein the structure is such as to increase the diameter and width of the insulator centrally where the supporting fixture attaches thereto and permitting the ends to be tapered off providing larger air gaps on the ends between the petticoat insulators and the body of the insulator. This is an important feature of the invention.

The simplified construction of my device obviates the necessity of two insulators and at the same time provides ractically a three in one fixture which inclu es the supporting fixture and the insulating means for the fuse. My self-insulated expulsion fuse and support is so constructed as to insulate in a most eflicient manner, the fuse wire and the por- 1926. Serial No. 128,412.

celain tube carrying the fuse wire providing self- 1nsulat1ng means with the outer porcelain supportin fixture which is adapted to be held by a single bracket or supporting arm. It is important that the whole fuse insulator and device is of sufficient strength to carry the other equipment to which it is attached and associated with.

These features together with other details and objects of the invention will be more fully and clearly set forth in the following specification and claims.

In the drawings forming part of this specification Figure 1 illustrates my self-insulated expulsion fuse and support with a choke as it would appear in use.

Figure 2 is a side view of my self-insulated expulsion fuse and support with a disconnect switch.

Figure 3 is a detail of a portion of my fuse showing the clamp for the air brake at the bottom of the same in plan view.

Figure 4 is a detail illustrating a portion of the fuse casing in cross section and show- 3;

ing the air brake clamp connected to the lower end of the porcelain casing.

Figure 5 is a side view of my self-insulated expulsion fuse with an insulator sup porting bracket.

Figure 6 is a cross section of my self-insulated expulsion fuse, a portion of which is broken away.

Figure 7 is a side view of my adjustable bracket ordinarily used for supporting my expulsion fuse.

Figure 8 is a plan View of a portion of the bracket illustrated in Figure 7.

Figure 9 is a plan view of the head piece of my expulsion fuse.

Figure 10 is a side sectional view of the expulsion chamber tube.

Figure 11 is a plan view of the expulsion chamber tube.

, Figure 12 is a side view of the expulsion chamber plug.

My self-insulated expulsion fuse and support is designed to be provided with a porcelain insulating member A having a series of petticoat insulating members 10 which are adapted to project from the body portion of the insulator A in a manner so as to provide an air gap 11 between each edge of the petticoats 10, and thus provide a dry air gap such as 12 between each petticoat member from the top to the bottom of the insulator A.

The insulator A is provided with a core or body portion 13 which supports the petticoat members 10 and which is adapted to taper from the center portion 14 to the upper end 15 and the lower end 16. The lower end 16 is formed with a portion for a short distance which is practically cylindrical.

It is preferred that the porcelain insulator A be made of the wet process porcelain tube construction and the same is designed with a central opening 17 which extends from one end to the other of the insulator A.

My self-insulated expulsion fuse is designed to be contained in and protected by the outer porcelain insulator A and is formed by the fuse wire 18 which preferably is of a single strand at the upper end and of a double or twisted strand nature such as 19 at the lower portion thereof. The fuse wire 18 is adapted to extend in its single strand nature through the removable explosion chamber tube 20 which is provided with the explosion chamber 21 and which is formed with a pair of lugs 22 on the upper end of the same which are adapted to rest upon the upper edge of the had piece 23.

The head piece 23 is provided with a downwardly depending annular flange portion 24 and an inner cylindrical tubular portion 25 which are adapted to fit over the upper end 26 of the insulator A in a manner so that the head 'piece 23 may be cemented securely to the end 26. In this manner the head piece 23 is firmly attached to the porcelain insulator A at the top thereof and in a manner so as to form a moisture tight joint between the head piece 23 and the insulator A. The head piece 23 is formed of metal and is adapted to provide a suitable cooling means for the explosion chamber tube 20, together with the other connecting parts which will be hereinafter described.

The explosion chamber tube 20 is adapted to be closed by the plug 28 which is threaded into the top of the explosion chamber tube 20 and is provided with a connecting screw 29 to which one end of the fuse 18 is connected, as illustrated in Figure 6. The explosion chamber tube is adapted to carry a fire proof liner tube 30 which extends through the passageway 17 and projects a short distance out of the lower end 16 of the insulator.

A. The size of the opening in the tube 30 determines the speed of expulsion of my selfinsulated expulsion fuse so that this may be in a sense regulated by a larger or smaller opening in the fire proof liner tube 30. The fire proof liner tube 30, together with the explosion chamber tube 20 are held spaced away from the inner surface of the chamber 17 of the insulator A to provide dry air space 3] about the fire proof liner tube and a considerable portion of the explosion chamber tube. This space 31 prevents the heat from the explosion of the fuse 18 in the explosion chamber 21 and in the fire proof liner tube from being extended directly against the inner surface of the insulator A and also provides the necessary air space to permit the drying out readily of the chamber 17 in the insulator should any moisture become apparent in this chamber. It is highly improbable under ordinary conditions that any moisture should extend into the chamber or passageway 17 so that ordinarily the space 31 acts as a dry air gap to protect the outer insulator A in a manner so as to prevent it from being overheated in the explosion of the fuse 18.

The explosion chamber 20 with the fire proof liner tube and fuse 18 are held firmly in place in the insulator A by means of the cap screw 34 which is threaded to the head piece 25 and is adapted to bear down against the plug 28 in a manner to hold the same rigidly in place. This holds the explosion chamber 20 and fire proof liner tube centrally within the insulator A.

The lower end of the fuse 18 is adapted to extend around in the loop portion 35 out of the lower end of the tube 30 and connect with the air gap clamp at 36 on one side of the air gap clamp 37. The air gap clamp 37 is securely attached to the lower end 16 of the insulator A and may be provided with a suitable lead liner so that the clamp may be rigidly attached to the insulator. The other side of the air gap clamp is adapted to support the line wire 38 which connects at 39 to the clamp 37. My clamp 37 is so designed that the distance from the lower end of the fire liner tube 30 around the loop 35 to the connecting point 36 is shorter than the distance from the end of the liner 30 to the connection 39, so that no arcing across to the line wire 38 will take place, the loop 35 burning off first in the expulsion and explosion of the fuse 18. The insulator A is provided with one or more petticoat insulating flanges 10 at the bottom so as to completely insulate with the desirable air gaps at the lower end of the insulator A to provide the necessary prevention to creepage of the electricity over the lower end of the insulator A and causing the expulsion fuse to operate through the loop 35.

My self-insulated expulsion fuse and support are provided with a supporting member B which is in the form of a bracket 40 designed to be connected in a suitable manner to support the insulator A projecting from the same. The bracket 40 is provided with an adjustable end arm 41 which is held by the bolts 42 extending through the slot 43 in a manner so as to adjust the arm 41 in relation to the portion 40 of the bracket B. The bracket arm 41 is formed with a loop portion 44 adapted to extend about the. enlarged central portion 14 of the insulator A and b means of a lead liner 45 the loop 44 may e clamped" firmly to the body of the insulator A and comparativel central between the upper and lower ends 0 the same. The outer olt 46 of the loop 44 which clamps the same to the insulator A is of anon-ma netic material so as to prevent an electrica circuit about the insulator A. T e bracket B functions with my self-insulated expulsion fuse to provide an electrical means wherein equipment of this nature is used of a very simple nature. Ordinaril two brackets with insulating caps would be emplo ed of the nature illustrated by the brackets having porcelain insulating heads E to support the electrical equipment and the expulsion fuses heretofore used; while with my self-insulated fuse and support only a single supporting member such as B is necessary, yet providing an eflicient insulator A and expulsion fuse supporting means which is sufficiently strong to support either the choke coil F or the switch S to provide a sufficiently rigid and substantial construction for electrical equipment. Thus it is ap arent that with my simplified construct-ion, y my self-insulated expulsion fuse and support that a practical expulsion fuse is provided of a more economical nature and wherein the parts are inter-changeable and replaceable, such as the explosion chamber tube 20, together with the fire proof liner tube 30 and the plug portion 28 with the cap 34. The explosion chamber tube 20 may be slipped up through the insulator A and I have provided slots 50 in the cylindrical portion 25 of the head piece 23 so that the lugs 22 may pass through the'slots 50 and then by rotating the liner 30 and explosion chamber 20 until the lugs 22 rest upon the u per edge of the head piece 23 as illustrated in Figure 6, the ex losion chamber 20 and liner 30 may be positioned within the insulating casing A. This construction ermits the parts to be placed within the insu ator A or readily removed by unscrewing the cap 34 and permitting the explosion chamber 20 with the liner to be lifted sufiiciently to withdraw from the top or permit it to be rotated and slide through the slots 50 and out of the bottom of the insulator A. This replaceable construction of my self-insulated expulsion fuse is very important, as should the liner become .damaged by the explosion of the fuse 18, a

new one can readily be inserted very quickly into the insulator A.

Ordinarily my insulated expulsion fuse with the casing A is adapted to be placed in the angular position as illustrated in Figures 1 and 2 and also in Figure 5, so that when the fuse 18 explodes the force of the explosion is away from the line wire 38 or other electrical equipment adjacent the lower end, but

it is evident that the same can be placed in vertical ppsition or in an desirable position so as to connected wi the ordinary electric equipment used with expulsion fuses of this. nature.

In Figure 5 I have illustrated the supporting bracket whichis formed with the base portion 54 and the insulating portion 55 which is interposed between the outer end 56 and the base portion 54. The portion 56 is adapted to be rovided with the loop 44 which extends a out the central portion 14 of the insulator A and clamps firmly thereto. vIn this structure the bracket R is provided with an insulating medium interposed between the ends of the same which may be preferred in some electrical hook-ups where a certain insulation is required to carry the load in my fuse.

The bore of the fuse chamber is variable obviously in accordance with the amperagev to be fused. In other words the bore varies directly with the capacity of the fuse itself, so that if the fuse is for a large amperage then the bore is larger and if the fuse is for a lower amperage then the bore is smaller. The bore of the fuse chamber varies according to the law of expulsion.

My sel finsulated expulsion fuse and support are designed to function together as the support is adapted to adjustably hold the body of the fuse insulating casing A and the same is designed to provide an expulsion fuse with a reduced height and wherein a small number of connecting points are provided for holding the fuse and casing, reducing the cost of installation, yet firmly providing the equivalent of expulsion fuses which have been used heretofore in an eflicient properly insulated expulsion fuse with the necessary dry air gaps and with the additional features provided by my particular and peculiar form of construction. In so far as I know my expulsion fuse is of a new type wherein the parts are replaceable and the fire proof liner tube is spaced away fromthe insulator A to provide a more efficient fuse and to protect the outer insulator A against being damaged in use under ordinary conditions by the explosion of the fuse such as 18, when the same is blown out by a heavy over-load in the line or by lightning which ordinarily blows out this type of a fuse. In these types of fuses the outer insulator A is many times damaged by the explosion of the fuse and the heat of the load is not properly dissipated through the head piece and explosion chamber. For this reason I have provided a suitably designed explosion chamber tube 20 of a nature to diffuse the heat from the fuse 18 to the head piece 23 and the connecting cap portion 34, so that the fuse 18 will not blow out under ordinary load where it is desirable that the fuse be exploded at such a time. Nevertheless, when the fuse is exploded the explosion chamber is properly constructed to take care of the same, having sufiicient strength and rigidity to stand the shock and force of the explosion, while the fire proof liner tube protects the casing A with an air gap 31 around the same. These types of construction of my fuses are of great importance in the providing of a device which is to be preferred over that type of expulsion fuses not having these types of construction and advantages.

In accordance with the patent statutes I have described the primriples of operation of my self-insulated expulsion fuse and sup port and I desire to have it understood that while I have illustrated a particular form of insulated expulsion fuses and support connected up in a particular way, it is obvious that the connections ma y be made in any suitable manner andvthat the detail of construction may be so "varied and applied to other uses than those above set forth without departing from the spirit of my invention, within the scope of the following claims.

I claim:

1. A self-insulated expulsion fuse including, a porcelain body member adapted to form the casing, a fire proof liner tube extending into and out of said porcelain body, an explosion chamber associated with said fire proof liner tube in a manner to be replaceable within said casing from the top thereof, and means for removably support ing said fire proof liner tube and explosion chamber within said casing.

2. A self-insulated expulsion fuse and sup port including, a porcelain insulating casing having a series of petticoat insulators spaced apart and extending from the outer surface thereof to provide a series of dry air gaps, an adjustable supporting member adapted to engage said casing between the ends thereof to provide a single supporting member for said fuse, and a fuse explosion chamber and tube adapted to extend through said casing, said tube and explosion chamber being spaced from said casing in a manner to provide a dry air gap therebetween to protect said casing.

3. A self-insulated expulsion fuse including, a porcelain casing, an explosion chamher, a fire proof liner tube of smaller diameter than said chamber, means for holding said explosion chamber and fire proof liner tube within said casing spaced from the same for the major part of the length thereof and adapted to contact and be sealed by said holding means at the top of said casing.

-l. An expulsion fuse including, a porcelain casing having a series of petticoat insulators spaced apart and arranged in adja cent relation to each other on the outer surface of said casing, said casing including a central portion of greater diameter than the ends of the same, a head piece adapted to be cemented to the top of said casing, a cap adapted to engage said head piece to seal the top of said fuse, and an explosion chamber and fire proof liner tube adapted to be held in said casing by said cap.

5. An expulsion fuse including, a metallic explosion chamber tube, lugs formed on the upper end of said tube, a porcelain casing, a head piece adapted to be cemented to said porcelain casing, channels extending through said head piece to permit the lugs of said explosion chamber tube to be passed therethrough to permit the explosion chamber tube to be inserted from the bottom of said casing and then rotated sulliciently to cause said lugs in said explosion chamber to engage against said head piece, a plug for closing said explosion chamber tube, and a cap for hearing down against said plug to hold said explosion chamber tube with the fuse hermetically sealed at the top of said fuse casing.

6. A self-insulated expulsion fuse and support including, a porcelain insulating casing having a series of petticoat insulators projecting therefrom, an enlarged central body portion formed in said casing, and an adjustable supporting bracket adapted to engage said central body portion of said casing.

7. An expulsion fuse and supporting means including, a porcelain casing, a tubular core body portion formed in said casing having an enlarged central portion with end parts tapering from said central portion toward the ends of said casing, a series of petticoat insulating flanges adapted to provide air gaps along said casing, and an adjustable bracketmember adapted to engage said enlarged central portion to form a single supporting means for said insulating casing, the expulsion fuse being contained in said casing.

8. A self-insulated expulsion fuse and support comprising an insulating casing, an adjustable bracket member for supporting said casing between its ends, a fuse adapted to extend through said casing, an expulsion chamber tube and fire proof liner tube through which said fuse is adapted to extend to provide a. fuse loop portion out of the bottom of said liner. and an air break bracket member positioned near the lower end of said casing adapted to support one end of the fuse loop on one side of said insulating casing and to support the line wire from the other side of said casing to permit the blowing of the fuse away from the line wire.

9. An expulsion fuse including, a casing formed of insulating material, a series of air gap insulators formed integral with said casing, a tubular passage through said casing, a fire proof liner tube extending out of the bottom of said casing, an explosion chamber tube connected to said fire proof liner tube and means at the top of said casing adapted to provide heat dissipating and distributin means and to seal hermetically the top of sai .fuse simultaneously clamping said explosion chamber and fire proof liner tube 1n said JOHN SUMPTER. 

